LANDING KINEMATICS OF HORIZONTAL BAR DISMOUNTS

Abstract

Dismounts from the horizontal bar require the dissipation of substantial velocities and therefore large forces. The maximum heights from dismounts are seen to be in the order of 4m or more. Kerwin et al. (1990) reported that maximum heights for double somersault dismounts -ranged from 3.45 to 3.73m,and for triple somersault dismounts, 3.89 to 4.08m. The purpose of this study was to investigate the biomechanical characteristics of succesful horizontal bar landings. Performances of six out of eight male finalists from the individual apparatus finals on horizontal bar at the World Gymnastic Championships1994, Brisbane, were chosen. The dismounts were recorded at 50 Hz during competitions, with the video cameras positioned on the catwalks above the floor of the competition venue. The analysis included mean and standard deviations of selected kinematic and temporal parameters in order to identify successful competition landing techniques. The recordings of the individual dismounts and subsequent landing performances were reviewed to qualitatively investigate the completion of the last salto of the double and triple back somersaults before the landing. The double back layout dismounts showed aback arched shape for most of the flight phase before re-piking in preparation for the landing. Analysis of the data revealed a mean maximum CM height during dismount, before the landing, of 3.06 m and an impact velocity at landing of-6.48 d s . Brueggemann et al. (1994), reported mean release velocities of 4.79 st 0.33 m/s for double tucked back somersault, 4.04 f 0.1 m/s for double layout back somersault, and 5.08 f 0.31 d s for triple tucked back somersault dismounts, which compares to the impact velocity of this study. The knee angle at landing was 156" and minimum knee angle during landing was 87". This available range of motion of 69" knee flexion with a landing phase duration of 0.14sec7 was a significant factor for the preparation phase of successful landings. The mean CM to ground contact and the horizontal was 87". Trunk to horizontal at landing was 134", and thigh to horizontal at landing was 107". Selected parameters of the results presented in this study may be used to form a representative biomechanical profile for horizontal bar landings.